Device for cutting a structure in a motor vehicle

Abstract

The technical field of the invention is that of motor vehicle safety involving devices for cutting a structure such as, for example, an instrument panel, so as to actuate a safety device. The object of the present invention relates more specifically to a device ( 1 ) for cutting a structure in a motor vehicle comprising a linear pyrotechnic charge ( 5 ) placed inside a flattened deformable tube ( 6 ), combustion of the said charge ( 5 ) bringing about deformation of the tube ( 6 ) which increases its cross section, the said deformation causing the structure ( 3 ) to break. The main characteristic of this device is that the combustion rate of the pyrotechnic charge ( 5 ) is less than 3000 m/s.

1 . Device for cutting a structure in a motor vehicle comprising a linear pyrotechnic charge placed inside a flattened deformable tube, combustion of the said charge brining about deformation of the tube which increases its cross section, the said deformation causing the structure to break, characterized in that the combustion rate of the pyrotechnic charge is less than 3000 m/s.  
     
     
         2 . Cutting device according to  claim 1 , characterized in that the pyrotechnic charge comprises a plurality of strands.  
     
     
         3 . Cutting device according to  claim 1 , characterized in that the tube is metallic.  
     
     
         4 . Device according to  claim 1 , characterized in that the tube is closed at each of its ends by a stopper so as to contain the pyrotechnic effects inside the said tube.  
     
     
         5 . Device according to  claim 3 , characterized in that the tube is made of aluminum.  
     
     
         6 . Device according to  claim 1 , characterized in that a space exists between the pyrotechnic charge and the tube, the said space being packed with a foam made of an elastomer.  
     
     
         7 . Device according to  claim 1 , characterized in that a device for igniting the pyrotechnic charge comprising an igniter is placed at one of the ends of the tube.  
     
     
         8 . Device according to  claim 1 , characterized in that the flattened tube is housed in a groove of the structure having a U-shaped cross section, the bottom of the groove including a secondary groove and the tube being held by means of a closure clip.  
     
     
         9 . Device according to  claim 1 , characterized in that the linear density of the pyrotechnic charge is less than 4 g/m.  
     
     
         10 . Cutting device according to  claim 2 , characterized in that the tube is metallic